For the dark chocolate cake:

1. Preheat the oven to 325 degrees F. Coat a 9-inch round cake pan with cooking spray. Set aside.
2. Place the dates and boiling water in a medium glass bowl and let sit 10-15 minutes.
3. In another medium mixing bowl, whisk together the flour, cocoa powder, baking powder and salt until combined. Set aside.
4. Drain the water from the dates and transfer the softened dates to a small food processor and pulse until a chunky paste forms. Alternatively, transfer the softened dates to a cutting board and chop until a smooth paste forms.
5. In another medium mixing bowl, use a hand mixer set on medium to beat together the oil and/or applesauce, sugar and eggs until light and fluffy. Beat in the date paste, milk and vanilla extract until combined.
6. Reduce the speed of the mixer to medium-low and slowly add the flour mixture to the wet ingredients until just combined.
7. Add the dark chocolate chips or chunks to the cake batter bowl and fold until just combined. Transfer the batter into the prepared cake pan and use the spatula to smooth it into one layer.
8. Bake 35-50 minutes or until a toothpick inserted into the center comes out clean (ovens greatly vary, so baking time will vary). Let cool on a wire rack.

For the date walnut frosting:

1. Place the dates and boiling water in a medium glass bowl and let sit 10-15 minutes.
2. Transfer the dates and the water to a blender or food processor. Puree until very smooth, scraping the sides as needed.
3. Add the cocoa powder, vanilla extract and salt to the food processor and puree until smooth.
4. Transfer to a bowl and fold in the walnuts and coconut (if using) until combined. Refrigerate until the cake has cooled, then spread the frosting on top. Cut into 10 slices.
5. Store the cake covered in the refrigerator.